Abstract
This article studies the impact of teacher absenteeism on education. Using data spanning three academic years on 285 teachers and 8,631 economically disadvantaged students from a United States urban school district, it tests assumptions that most teachers' absences are discretionary and reduce productivity, students' mathematics and reading scores. When a teacher is replaced by a less experienced substitute, instructional intensity and consistency may decline: ten days of teacher absence reduces students' achievement scores by about half a point. For some students, this could translate into a lower classification category, thus lowering their motivation to succeed.